Our overall objective continues to be the understanding of mechanism, structural foundation and regulation of basic biological processes involving movement at the subcellular level. Analysis of these processes demands new methods since typically they involve movement mechanisms not encountered in nor easily understood by comparison with the macroscopic workd; yet they are often at the root of cell and organ functions necessayr to the existence of the organism. Chromosome movement, mitotic spindle assembly and movement, cell division, fertilization, gametogenesis, axostylar movement and cytoplasmic streaming are among the processes we examine. We approach this objective by developing and applying new optical, mechanical, thermal, photochemical, electro-optical, electro-mechanical and other methods which allow measurementment of physical parameters directly in localized regions in functioning living cells. Thermodynamic analyses and model building as well as studies of the basic physical principles underlying the measurements are an integral part of this effort.